GCSE AQA Physics

GCSE AQA Physics

1. Energy transfers

   • Energy can be transformed from one form to another.
   • It involves changing one form of energy into more than one form of energy.
   • Examples: Match head (chemical) = light + heat. Solar power music box (light) = sound.

2. Energy efficiancy

   • A measure of how well an object uses the energy that is supplied to it.
   • Calculated by: Efficiency = useful energy transferred by the device % total energy supplied to the device x100
   • Examples: 60J useful + 200J supply. Efficiency = 60%20 x100 = 80%

3. Cost/paying for electricity

   • E=PxT. Energy (kilowatt hours - KWH). Power (kilowatt - KW). Time (hours - H)
   • cost = number of units (energy transferred) x cost per unit.
   • Examples: 0.5 KW x 2 H = 1 KWH. 1 unit = 8p cost = 1x8 = 8p.

4. Most Kids Hate Learning GCSE Energy Names.

   • Magnetic, Kinetic, Heat, Light, Gravitational, Chemical, Sound, Elastic potential, Electrical, Nuclear.

5. Sankey diagrams

   • 100J input, 10J output, 90J wasted. Efficiency = useful%total x100.

6. Renewable energy

   • Solar
     • Sun's heat and light are turned into: electrical energy by solar cells, or used to heat water in homes using solar panels.
       • Advantages: Renewable + no pollution.
       • Disadvantages: Expensive + unreliable
   • Wind
     • Wind turbines turn kinetic energy into electrical.
       • Advantages: Renewable, no pollution, cheap, easy to build, nothing burnt.
       • Disadvantages: unreliable + noisy/ugly.
   • Tidal
     • High tide the water is trapped behind a dam. Tide goes out, the turbine moves making the generator make electrical energy.
       • Advantages: Renewable, no pollution, reliable, cheap to run.
       • Disadvantages: flooding + expensive to build.
   • Geothermal
     • Turn heat energy from the Earth's rocks into electrical.
       • Advantages: renewable, no pollution.
       • Disadvantages: Hard to put in place, expensive.
   • Biomass
     • Plant's Chemical energy turned into heat/electrical.
       • Advantages: renewable, easily used.
       • Disadvantages: large areas of land are needed.
   • Hydroelectric
     • Dam transfers rivers kinetic energy into electrical.
       • Advantages: Renewable, no pollution, store water.
       • Disadvantages: expensive to build, ruin environment.
   • Wave
     • Machines turn the waves kinetic energy into electrical.
       • Advantages: renewable, no pollution, nothing burned.
       • Disadvantages: needs lots of machines, expensive, machines look ugly, damage.

7. Non-renewable energy

   • Coal, oil and gas are all fossil fules. They are burned to make heat. Nuclear reactions in nuclear fules release heat.
   • Chemical energy is stored in fossil fules.